Results 1 to 10 of 10

Thread: creedmore sports new scale

  1. #1
    Join Date
    Oct 2019
    Posts
    733

    creedmore sports new scale

    they have introduced a new scale.
    low cost and direct "grain" readout.
    some are concerned that other scales my lose "accuracy" in math conversions.
    the possible down side is the scale is straight load cell technology, not magnetic dampened.
    looks like it would be ok for a low volume loader at home.
    NOW we need someone to buy one and report ??

  2. #2
    Join Date
    Jul 2016
    Location
    Surprise, AZ
    Posts
    364
    Quote Originally Posted by rsmithsr View Post
    they have introduced a new scale.
    low cost and direct "grain" readout.
    some are concerned that other scales my lose "accuracy" in math conversions.
    the possible down side is the scale is straight load cell technology, not magnetic dampened.
    looks like it would be ok for a low volume loader at home.
    NOW we need someone to buy one and report ??
    I can assure the skeptical that they are not losing any "accuracy" in math conversions. Load cells, etc read out in volts, not any measure of mass/weight, which are digitized using an Analog to Digital converter. From there the conversion from bits to any unit of your choice is identical. It would be a very naively made system that performed a conversion from bits-to-something and then converted from *that* to something else. Furthermore any of these devices are likely to run off of a 32-bit processor, but even if they're only 16-bit they have more mathematical precision than you will ever be able to make use of in real life.

    GsT

  3. #3
    Join Date
    Oct 2019
    Posts
    733
    gene i do not buy it either.
    i know guys that use the fx120i in grams,
    because it is more "precise" more digits in the readout.
    i do not even try to talk to them
    my OPINION is that creedmoor has taken the trend,
    and marketed to it.

  4. #4
    Join Date
    Dec 2003
    Location
    washington.........STATE that is.
    Posts
    11,583
    "More accurate" and "less accurate" math....... I'm w/Smith, I can't even carry on a casual conversation with these people.

    It's like playing chess with a pigeon

    Or "arguing" with someone who thinks solar energy or electric cars are saving the planet

    Now the mechanics of the scale??? I know nothing about. But I do have 11 scales, and like my calipers and mics and chronographs I can just check them one against the other.

    I wonder does CS take bitcoin.....hmmmm....

  5. #5
    Join Date
    Jul 2005
    Posts
    676
    A/D converters have a couple of different properties that can contribute to errors.
    Resolution is the first one.
    How many bits does the converter use to determine a value.
    A 10 bit converter has 1,024 possible values.
    Each additional bit doubles the number of possible values.
    12 bits produces 4,096 values.
    14 is 16,384.

    The 'value' of each bit is a function of the range (in whatever unit you care to use).
    The range is set by whatever gain the output of the D/A and its amplifiers are set up
    to produce.Many A/D converters have a nominal 1 volt input range.
    Over that 1 volt range there are gain errors, linearity, and
    offset errors.
    In many cases there is also some 'digital curve fitting' coming into play.

    This is the reason for multiple points in the setup.
    Commonly simple curve fitting will use zero, and a single weight near maximum.

    More sophisticated curve fitting might use 0, 1/4 of the range, 1/2 of the range, and then a fill scale setting.
    Easily accomplished with a set of weights that are equal.

    Generally the more points there are the better.
    One simple trick is to use a larger number of equal weights.
    This allows the simple use of the same value of weights.

    There are high resolution 'successive approximation' converter.
    They can get into 20 bits and higher.
    Last edited by brickeyee; 12-10-2021 at 02:25 PM.

  6. #6
    Join Date
    Feb 2003
    Location
    Poetry, Tex.
    Posts
    7,041
    Quote Originally Posted by brickeyee View Post
    A/D converters have a couple of different properties that can contribute to errors.
    Resolution is the first one.
    How many bits does the converter use to determine a value.
    A 10 bit converter has 1,024 possible values.
    Each additional bit doubles the number of possible values.
    12 bits produces 4,096 values.
    14 is 16,384.

    The 'value' of each bit is a function of the range (in whatever unit you carer to use).
    The range is set by whatever gain the output of the D/A and its amplifiers are set up
    to produce.Many A/D converters have a nominal 1 volt input range.
    Over that 1 volt range there are gain errors, linearity, and
    offset errors.
    In many cases there is also some 'digital curve fitting' coming into play.

    This is the reason for multiple points in the setup.
    Commonly simple curve fitting will use zero, and a single weight near maximum.

    More sophisticated curve fitting might use 0, 1/4 of the range, 1/2 of the range, and then a fill scale setting.
    Easily accomplished with a set of weights that are equal.

    Generally the more points there are the better.
    One simple trick is to use a larger number of equal weights.
    This allows the simple use of the same value of weights.

    There are high resolution 'successive approximation' converter.
    They can get into 20 bits and higher.
    Kinda like my beam scale with the ceiling fan on.

  7. #7
    Join Date
    Jul 2005
    Posts
    676
    Quote Originally Posted by Butch Lambert View Post
    Kinda like my beam scale with the ceiling fan on.
    The ceiling fan will screw up digital scales just fine also.

  8. #8
    Join Date
    Feb 2003
    Location
    Florida Panhandle
    Posts
    686
    Quote Originally Posted by rsmithsr View Post
    gene i do not buy it either.
    i know guys that use the fx120i in grams,
    because it is more "precise" more digits in the readout.
    Well, they should get their scale calibrated in tons. It will have lots of digits and be very precise.

  9. #9
    Join Date
    Jul 2005
    Posts
    676
    I remember having to explain to another PhD EE that
    "not all the digits on a frequency counter" mean something.

    He really had no idea of how the accuracy of the gate counter in the unit was only about 1E-6.
    He accused me of wasting money on an extremely accurate reference oscillator to lock the counter to.

    We ended up renting an atomic clock to get enough digits to be useful in testing our EW system.

    And even that unit had to be in a temperature controlled screen room to get what we needed.
    Output accuracy still depended on the unit being at 65 F, +/- 1 F.

    That allowed us to have an accuracy of around 1e-16.
    Last edited by brickeyee; 12-10-2021 at 02:34 PM.

  10. #10
    Join Date
    Dec 2003
    Location
    washington.........STATE that is.
    Posts
    11,583
    Thank You TomD!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •